Ebstein's anomaly تشوه ابشتاين
INSTRUCTION Listen to this patient's heart. He was told he had an innocent murmur during a school medical examination many years ago but now has a large globular heart on chest radiography. SALIENT FEATURES History · An incidental cardiac murmur. · Ask the patient about palpitations (paroxysmal supraventricular tachycardia). · Symptoms of right-sided heart failure. · History of maternal lithium ingestion. Examination · Raised jugular venous pulse; a large 'v' of tricuspid regurgitation is absent because the giant right atrium absorbs most of the regurgitant volume. · Left parasternal heave. · Loud first heart sound produced by the sail-like anterior tricuspid leaflet. · Pansystolic murmur which increases on inspiration. · Hepatomegaly. Proceed as follows: · Ascertain whether the patient has exertional cyanosis or dyspnoea. · Exclude an atrial septal defect. DIAGNOSIS This patient has isolated tricuspid regurgitation (lesion) which is probably of con-genital aetiology as there is no pulmonary hypertension. He has Ebstein's anomaly with cardiomegaly and cardiac failure (functional status). Read recent paper on this condition: J Am Cull Cardiol 1994; 23: 170-6. ADVANCED-LEVEL QUESTIONS What is the pathology in Ebstein's anomaly? The tricuspid leaflets are abnormal and are displaced into the body of the right ventricle. The septal leaflet is variably deficient or even absent. The posterior leaflet is also variably deficient and there is a large 'sail-like' anterior leaflet that is the hallmark of this condition. The abnormally located tricuspid orifice results in a part of the right ventricle lying between the atrioventricular ring and the origin of the valve, which is continuous with the right atrial chamber. This proximal segment is known as the 'atrialized' portion of the right ventricle. About 50% of the patients have either a patent foramen ovale or a secundum ASD, and 25% have one or more accessory atrioventricular conduction pathways. The anomaly is said to be associated with maternal lithium ingestion. What are the mechanisms of cyanosis in these patients? Right-to-left shunting at the atrial level, i.e. through a patent foramen ovale or atrial septal defect. What are the predictors of a poor outcome? · The earlier the presentation, the higher the risk of mortality. · A large right atrium or cardiothoracic ratio >60%. · Severe right outflow tract abnormalities. How would you investigate such a patient? · CXR: large right atrium with oligaemic lung fields. · ECG: RBBB (right bundle branch block), prolonged PR interval, P pulmonale (indicating right atrial enlargement), the P waves are large (Himalayan P waves) type B Wolff-Parkinson White syndrome (where the QRS complex is downward in lead V 1 ). · Echocardiogram: characteristic findings include the abnormal positional relation-ship between the tricuspid valve and mitral valve with septal displacement of the septal tricuspid leaflet. · Cardiac catheterization: in classical cases there is no place for this investigation, which in the past has been associated with serious morbidity and mortality. What are the indications for surgery? · Severe functional limitation. . A cardiothoracic ratio >60%. · An atrial communication and if the patient has cyanosis (due to risk of stroke). · Accessory pathway is present. · Severe tricuspid regurgitation. How are such patients treated? · Tricuspid valve replacement plus closure of the atrial septal defect. · Tricuspid annuloplasty with plication of the atrialized portion of the right ventricle. W. Ebstein (1836-1912), German physician who also described Armanni-Ebstein nephropathy (where there is glycogen vacuolation in the proximal convoluted tubules); L. Armanni (1839-1903) was an Italian pathologist.